Vacuum-valve detector



R. A. WEAGANT.

VACUUM VALVE DETECTOR.

APPLICATION FILED MAR. 10. mm.

Patented May 31, 1921.

UNITED STATES PA TENT OFFICE.

BOY ALEXANDER WEAGANT, OF ROSELLE TOWNSHIP, UNION COUNTY, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 RADIO CORPORATION OF AMIIEIRIOA, A

CORPORATION OF DELAWARE.

VACUUM-VALVE DETECTOR.

Specification of Letters Patent.

Patented May 31, 1921.

Application filed March 10, 1917. Serial 110. 153,985.

To all whom it may concern:

Be it known that I, ROY ALEXANDER WEA- GANT, a citizen of the United States, residing in the township of Roselle, county of Union, and State of New Jersey, have invented or discovered certain new and useful Improvements in Vacuum-Valve Detectors, of which the following is a specification.

This invention relates to vacuum valve devices used to detect or amplify electrical oscillations of audio or radio frequenc of the general type described in Fleming S. Patent 803,684, and particularly to those having a structure similar to the valve disclosed in my Patent No. 1,289,981, Dec. 31, 1918.

In using devices like that shown in my said application, comprising an exterior control element, which element, when its potential is raised by a received impulse, projects an electrostatic field into the path of the electron stream, difiiculty has been experienced from strong electrical disturbances which rendered the tube or valve temporarily inoperative, varying in time from a fraction of a second to ten or fifteen minutes. This difficulty is of a serious nature in the commercial use of the device as in-' terruption of the functions of the tube occur every time such strong electrical disturbances take place. The object of this invention is to overcome or obviate the defects named. I accomplish the object of my invention by the improved device hereinafter described.

My improved device comprises a vacuum tube, two electrodes, one of which is preferably heated, and an outside control element or electrode. The hot and cold electrodes are so formed and disposed in the tube that the mean distance between them is relatively great as compared with the distance between two oints or areas, one on each electrode, whic are adapted to form points between which the electron flow will be continuous and uninterrupted in the presence of disturbing causes, 2'. e., static, and high potential transmitted impulses.

In the drawing accompanying and forming a part of this specification, I have illustrated the preferred embodiment of my mvention, and also two modifications.

Figure 1 shows the complete vacuum tube with its two inclosed electrodes, and the exterior control electrode.

t Figs. 2 and 3 show modifications in strucure.

The tube, It, is formed of glass, and is evacuatedfto any desired degree, and con tains the filament f, preferably of tungsten, formed with an acute angle or point 6. The cold electrode is a late of metal, as shown at 0 in Fig. 1, or it may take the form of a pin, 0, including a few helical convolutions 20 as shown in Fi 2, or it may be in the form of a conoida? shell as shown in The control element, e, is preferably a c linder of brass or co per fixed firmly onto t e exterior surface oi tube, t, and it preferably incloses all the active area of electron flow.

The circuit shown in Fig. 1 is now well known for use with vacuum detectors. The antenna, a, adjustable inductances 9 and 10 associated as transformer coils, and the adjustable condensers, 12, are arranged in a well known way. The battery, as, is in circuit with head telephone 14, and is connect ed by circuit 15 to cold element, 0, and hot element, f. The heating battery, 16, and adjustable resistance, 17, are connected in the well known way to the filament. The electrical connections, 18, 19, electrically unite cold element, c, and control element, 0, to opposite terminals of coil, 10, and the condenser, 12.

In operation, by proper adjustment of battery, ac, the heating means, 16, 17, and the condensers, 12, the tube may be used as a detector, amplifier or oscillator.

When static or other effects tend to cause the tube to become plugged, that is, to suspend its functions, the small gap between the electrodes operates to keep the electron flow from ceasing entirely, and thus prevents the accumulation of a charge on the interior of the walls of the tube. The small gap, moreover, does not interfere with the normal operation of the device, because the greater portion of the electron stream between the electrodes is subject to variations due to the electrostatic field of the control element, just as if the small gap were not present. The practical result of the arrangement, as s own by actual use, is that the valve clears itself of any electron acremains at all times res cumulations from disturbing-sources, and

nsive to variations in the electrostatic eld of the control element, e.

In addition to use as a detector of electrical oscillations or im ulses, this device is also useful as an ampl' er of electrical variations of all kinds, including both radio and audio frequency oscillations, and it may be employed in wire conductor telephoning and as a repeater to amplify weak, received impulses at one point and relay them to another point with increased energy and absolute fidelity of reproduction.

What I claim is:

1. In a device of the kind described, a vacuum chamber, two electrodes sealed in said chamber, means for heating one of said electrodes, the said electrodes being spaced from each other and so arranged that the mean distance between said electrodes is relatively great as compared with the distance between a point on one and a point on the other, in combination with a control element located outside said vacuum chamber.

2. In a device of the character described, a vacuum tube, a cold electrode, a hot electrode in the form of a, filament having an acute angle fixed in close proximity to a cold electrode, said electrodes being arranged to have a relatively eat mean distance separating them an presentin a minimum distance at said filament ang e.

3. In a device of the kind described, a vacuum chamber, two spaced electrodes sealed in said chamber, and means for heating one of the electrodes, one of said electrodes having a pointed portion in close proximity to the other electrode and the mean distance between said electrodes being relatively great as compared with the distance between the pointed end and the other electrode.

4. In a device of the character described, in combination, an evacuated vessel, an anode and a heated cathode in said vessel having a relatively great mean distance therebetween, and an electrostatic control element surrounding said vessel and extending substantially parallel to the path of the electron stream therein, said cathode having a sharp angle pointing toward said anode and in close proximity thereto.

5. In a device of the character described, a vacuum tube, a cold electrode, a hot electrode in the form of a filament having an acute angle fixed in close proximity to said cold electrode, said electrodes being arranged to have a relatively great mean dis tance between them and presenting a minimum distance at said filament angle, and an exterior control element extending from the zone of said cold electrode to the zone of the portion of the active surface of said cathode farthest therefrom.

6. In a device of the character described, in combination an evacuated vessel, an anode and a heated cathode in said vessel having a relatively great mean distance therebetween, an electrostatic control element surrounding said vessel and extending substantially arallel to the path of the electron stream t erein, said cathode having a sharp angle pointing toward said anode and in close proximity thereto, and means whereby the potential of said control element is varied by signal waves during the operation of the device.

ROY ALEXANDER WEAGANT. 

